Since 1975, Michael Reese Hospital and Medical Center (MRH/MC) in Chicago has had in place a continuing program to upgrade and improve laboratory animal facilities to meet the standards set by the American Association for Accreditation of Laboratory Animal Care (AAALAC). During 1982, following extensive renovation and new construction, the then newly centralized laboratory animal facility at MRH/MC was fully prepared for accreditation by AAALAC which was granted on October 11, 1983. The purpose of this application to the Animal Resources Branch of Research Resources is to provide stainless steel isolation cubicles for rodents and rabbits that will allow the laboratory animal resource facility to provide optimum isolation and quarantine to newly admitted animals and to separate critical experiments by investigator or by strain and vendor as appropriate. Consequently, the quality of animal care will improve considerably as our ability to effectively minimize the introduction of disease agents into established colonies will be significantly enhanced. Our ability to provide such adequate isolation and quarantine has been severely curtailed by the need to upgrade baboon housing in compliance with recent national animal welfare legislation. As a consequence, baboon housing space had to be doubled which reduced the space otherwise available for quarantine, isolation, separation and overflow. The use of isolation cubicles provides an efficient and effective way to restore this much needed flexibility in space utilization to the animal care operation. Subdivision with cubicles will restore 17.5% or 499 net square feet to the small animal pool. It is essential that the Michael Reese Hospital and Medical Center Animal Care and Use Program continues to maintain the high standards set by the American Association for the Accreditation of Laboratory Animal Care especially in this most sensitive area of disease control in the appropriate use of isolation and quarantine.